I've only ever made the regular noncooked buttercream - just wondering if there's really any difference in the two types?

What do you mean by "cooked?" Do you mean the meringue buttercreams like IMBC and SMBC or a flour based buttercream like Seven Minute Frosting?

There is a tremendous difference in taste and texture. I prefer Italian Meringue Buttercream (IMBC). It's very satiny and smooth and has a more elegant texture to it. Classic American buttercreams (non-cooked), are made with powdered sugar and fat (either shortening, butter, or a combination of the two). Icings made with all powdered sugar (IN MY OPINION-some people get touchy about this) are very gritty and heavy. My husband says it "feels harsh in the throat."

Meringue buttercreams do not crust so a paper towel smoothing method will not work for smoothing. Seven minute frosting recipes using cooked flour are usually very soft and in my opinion not suitable for decorating besides borders. My husband's grandma makes the DH strawberry cake mix with a seven minute frosting and it is honestly one of my favorite cakes.

Are you refering to the BC that use egg whites in natural form? I would like to know too.

Yes, with egg whites. I was just looking at a recipe in the Whimsical Bakehouse book that used egg whites and was cooked. I didn't realize that these types don't crust though - so now I understand why we use the American style so much.

Thanks - this has helped!